Proteins

Question 1

what are the monomers of proteins?

Answer 1

amino acids

Question 2

what do amino acids consist of?

Answer 2

• carboxyl group
• amine group
• side chain

Question 3

how many different amino acids are there?

Answer 3

20 amino acids

Question 4

how do the amino acids vary?

Answer 4

by having different side chains

Question 5

why are some proteins essential?

Answer 5

need them in diet otherwise lead to protein malnutrition

Question 6

what does it mean if proteins are non-essential?

Answer 6

the body makes them

Question 7

which organ makes proteins?

Answer 7

liver

Question 8

list 10 uses of proteins

Answer 8

• structure
• hormones
• pumps
• transport
• antibodies
• cell recognition
• receptors
• toxins
• blood clotting
• storage

Question 9

how many amino acids form a dipeptide?

Answer 9

two amino acids

Question 10

what type of reaction forms dipeptides/ polypeptides?

Answer 10

condensation reaction

Question 11

what are two types of functional proteins?

Answer 11

• fibrous

- globular

Question 12

what are the properties of fibrous proteins?

Answer 12

• made of long fibres
• coil into long helices (due to regular pattern of hydrogen bonds)
• strong - structural function - protection
• insoluble

Question 13

what are properties of globular proteins?

Answer 13

-fold into balls/ globules
- soluble
-biochemical function: enzymes most common because shape has active site
(function depends on tertiary structure)

Question 14

name three types of fibrous proteins

Answer 14

• collagen
• keratin
• chitin

Question 15

name two types of globular proteins

Answer 15

• haemoglobin

- myoglobin

Question 16

describe collagen

Answer 16

• it is a fibrous protein
• made of three polypeptide chains
• 30% glycine (simple amino acid with hydrogen as side chain)
• tightly wound and compact

Question 17

describe haemoglobin

Answer 17

• it is a globular protein
• made of 4 polypeptide chains
• 4 haem groups Fe 2+ ions which carry oxygen

Question 18

what is primary structure?

Answer 18

sequence of amino acids in a polypeptide chain

Question 19

what is secondary structure?

Answer 19

• hydrogen bonds pull chains into regular pattern either alpha-helix or a beta-pleated sheet

Question 20

what is tertiary structure?

Answer 20

3D shape that occurs due to the bonding between R groups

• hydrogen bonds
• ionic bonds
• disulphide bridges

Question 21

what is quaternary structure?

Answer 21

tertiary structure for two or more polypeptide chains